/Engine/Source/Runtime/Core/Public/GenericPlatform/GenericPlatformMath.h
Please note that we don't define what happens in the case of NaNs as there might be platform specific differences.
ValueGEZero if Comparand >= 0, ValueLTZero otherwise
static constexpr float FloatSelect ( float Comparand, float ValueGEZero, float ValueLTZero )